Power disks brakes, brake pedal goes to floor

[rose heiden]

1970 rr. Changed front pads, turned rotors and bled master brake cylinder and brake lines. Shaved the caliper mounting braket on left front to make a more square fit. Pedal didnt go all the way to floor before this was done now it does. Calipers, pads and rotors r from a 74 roadrunner. Please advise what the problem is. Appreciate it.

 

[Autorotica]

Bad Master or air in system... No other options.

Chris

 

[rose heiden]

Thanks. Thought so. Which do u suggest, rebuild master or buy new one? Does the master have to match the 74 rr disc brake system or can I actually buy a 70 rr master to match year of car? Also how do we stop the braking pulling to right front? It drives down the road straight, so we don't think front end alignment will fix problem.

 

[Russ69Runner]

Maybe a shim plate you can get for the left side. So they will pull even. Or possible you may need to drive it more to brake them in. It's always some thing even small but large.

 

[rose heiden]

Thanks. We just looked and there are shim plates on right and left pads. We'll take the right side off and try that. We'll let u know

 

[Plybeep68]

What master cylinder do you have on the car now? Did it come with disc oringally ?

 

[rose heiden]

Sorry, we don't know. Previous owner didn't disclosed anything to the classic car dealer that we brought it from.

 

[69hemibeep]

Lets get to basics. I don't mean to be insulting as to your capabilities with the questions but we need to know some background.
1 Is this a disc drum car?
2 I take it you didn't work on the rear?
3 Did you support the calipers while doing the work or let them hang on the brake hoses?
4 Did you open up the system anywhere prior to bleeding?
5 How did you collapse the calipers to make room for the new pads?
6 Did you pump the brakes up prior to bleeding to get a pedal?
7 What method of bleeding did you use?

 

[rose heiden]

All disc. No work done by me. They work well. Supported calipers while working on them. Yes, opened at calipers to collasp them by using large plumbers plyers. Put back together and that's when break pedal went all the way to floor. Had appt with a mechanic shop two days later so they did the bleeding of the system so don't know how they did it. Does this help?

 

[69hemibeep]

When the pedal first went to the floor did you try pumping it a few times? Its not uncommon to have no peddal at first.

 

[rose heiden]

Yes, we did. Still went to floor. So we ordered a master cylinder to replace the one on it

 

[quikbird]

Master cylinder is notorious for hiding air in it even while trying to bleed it

 

[rose heiden]

Yes, thank you

 

[69hemibeep]

It's in a shop so there is no way of knowing what they are doing. Hope it works out.

 

[rose heiden]

Ya, know what u mean. But I can trust them somewhat. They called us in while it was on lift to show us a motor mount they replaced that was bad and fixed what my husband did, packing of bearings. Our trusted old mechanic referred us to this shop. Only has 3 mechanics plus the owner/mechanic. Old mechanic won't work on classic cars. Classic car mechanic shop is 1 and 1/2 hours from me

 

[Russ69Runner]

Way to go Girl. Get out the way guy's their is a Girl runner coming through. Good to see a woman runner owner.

 

[rose heiden]

Appreciate it. Had a 70 rr when I was 19 in 1971. Loved to drive fast to blow out the carb. Going to take this one to a local track. See if me and my baby still haveit in us.

 

[Russ69Runner]

Sound's like your going to have a grate time with the car. Yes nothing like the sound of the motor and the thrill of driving these car's. I am getting close to having this one on the road. Shooting for June when my birth day is. Have four speed manual trans. and love to shift gears. Keep us up on the car and what your doing. Hope you get the brake thing worked out.

 

[rose heiden]

Update on brakes. When mechanic went to change out master cylinder he found that the linkage on rods between booster and pedal and from booster to master cylinder needed adjustment. So taking new master cylinder back to oreilys.
Good to go to classic car meet and greet this Sat. Beep beep!!

 

[Russ69Runner]

Good new Rose. Glad the mechanic found the problem. Now you can enjoy your runner.